Nailable steel joist



May 7, 1968 A. DAVIS, JR

NAILABLE STEEL JOIST Filed June 24, 1966 United States Patent O 3,381,433 NAILABLE `STEEL 10181 Augustine Davis, Jr., Washington, DC., assigner to Davisbilt Steel Juist, inc., Washington, DE., a corporation of Delaware Filed .lune 24, 1966, Ser. No. 560,164 4l Claims. (Cl. 52--364) ABSTRACT F THE DISCLGSURE A nailable joist for supporting a collateral member having a planar unitary flanged steel web of impenetrable heavy gauge structural steel, with an integral nail penetra'ole portion extending continuously along said flange provided by a groove rolled into the interior surface of the flange.

This invention relates to a metal joist for building constructions providing for the nail fastening of collateral surface materials to the joist by nails driven directly through the chord of the joist.

It is an object of the present invention to provide a metal joist which combines the full advantages of metal joists with the nailability of wooden joists.

It is another object of the invention to provide a nailable metal joist which is substantially identical in strength, external dimensions, and cost to conventional metal joists, and directly substitutable therefore, yet which joist provides ready nailability thereto of wooden flooring, ceiling panels, or other collateral members.

It is a more specific object of the invention to provide a nailable metal joist which may be constructed of generally conventional heavy gauge load bearing steel throughout, yet which provides a nail penetrable fastening portion. The joists of the invention includes a unitary steel chord having a generally planar flange of nail impenetrable heavy gauge steel, and a minor thinner liange portion which is nail penetrable defined by a groove extending into the interior surface of the flange.

Other objects and advantages of the invention will be apparent from the following specification when read with the accompanying drawings in which certain embodiments of the invention are illustrated by way of example and wherein:

FIGURE l is a side elevation of an exemplary nailable metal joist embodying the principles of the invention and illustrating a section of wooden flooring nailed thereto;

FIGURE 2 is a cross-sectional view taken along the line 2--2 of FIGURE l;

FIGURE 3 is a cross-sectional View similar to that of FIGURE 2 illustrating a second embodiment of the invention; and

FIGURE 4 is a cross-sectional view similar to Fi"- URE 2 illustrating a third embodiment of the invention.

Various types'of nailable metal josts are presently known in the art. However, they require special nonconventional constructional materials. Specifically, these prior joists have been constructed with nailable portions made from special and separate thin metal members, which nailable members were either a substitution for, or in addition to conventional gauge construction members.

Referring now to the drawings, in FIGURES l and 2 there is illustrated a first embodiment of the invention in which the metal joist is indicated generally by the reference 10. This metal joist includes a web 11 which may be of any suitable construction and is shown here as a conventional open web lbent bar stock type. The metal joist lil further includes a pair of identical opposing chord members 12 and 1li. The chord members 12 and 14 here together define the top chord of the joist and are conventionally welded along the top edge of the web 11 on opposite sides of the web 11. The chord members 12 and 14 are here shown supporting a wooden flooring 16 by nails 18 which extend down through the flooring 16 and through a chord member 12 or 14. A conventional bottom chord 20 and joist end member 22 may also be provided.

Considering now in further detail the exemplary chord members 12 and 14 of the metal joist 1f) of FIGURES l and 2, they are preferably identical L-shaped one-piece steel angles each comprising two generally planar legs at right angles to one another, a vertical -leg 23 and a horizontal leg or liange portion 24. For manufacturing purposes, it is desirable that both legs be substantially identical, with an equal section for both legs, so that they will not distort in hot rolling for example. It may be seen that each chord member 12 or 14 is a completely unitary steel member. By the term unitary herein, both in the specification and the claims, a single homogeneous member is meant. The term unitary is not meant herein to include such integral assemblies as, for example, a nailable member welded or otherwise secured to a load bearing member.

Considering the horizontal leg or flange portion 24, it may be seen that this entire flange portion is ofa uniform, conventional, heavy structural gauge thickness and nail impenetrable except for a minor intermediate portion 26. The minor intermediate portion 26 is a region of substantially thinner gauge metal than the principal portion of the flange portion. This minor intermediate portion 26 is of a gauge of metal of a thinness penetrable by nails.

Preferably, the entire exterior or upper surface of the upper surface 28 of the horizontal leg 24 is planar so as to provide a continuous support yand abutment of the overlying wooden flooring 16 or other -collateral member. The interior surface 30 of the horizontal leg 24, i.e. the surface opposite the exterior surface 28, is preferably recessed at the intermediate portion 26 to form said intermediate portion by the forming of a uniform groove 32. The groove 32 is preferably of a uniform depth sucient to leave only the desired thin, nail penetrable thickness of metal at the intermediate portion 25 between the bottom surface of the groove 32 and the. exterior surface 28. Preferably, the shoulders or transition region at the edges of the groove 32 are rounded to avoid stress concentrations. It may be seen that the groove 32 is preferably planar and of a uniform width and extends evenly and longitudinally along the length of the chord member so as to provide a continuous nail penetrable strip along the entire length of the metal joist 10. Preferably, the horizontal leg or flange portion 24 is identical for both chord members at both sides of the metal joist 10 so as to provide a nail penetrable strip along both sides of the joist. The chord members 12 and 14 are otherwise substantially structurally identical to conventional metal joist chord members.

There is a substantial portion of the horizontal leg 24 to the outside of the intermediate portion 26. This portion provides support for the intermediate portion 26, increases overall strength and prevents substantial deformation or bending of the intermediate portion when the nailing is accomplished.

Preferably, the groove 32 is formed into the chord members 12 and 14 by hot rolling, cold forming or other suitable processes. One of the advantages of the invention is that the groove 32 may be formed simultaneously with and as part of the same process as the hot rolling or cold forming processes in which the basic shape of the chord member is formed. The actual manufacturing costs for the chord members 12 and 14 are substantially identical to that for the conventional chord members for metal joists. Accordingly, since the chord members 12 and 14 may be assembled with the web 11 in the same manner as for a conventional metal joist, the overall cost of the metal joist 10 may be virtually identical to that of conventional metal joists of the same type not providing the advantages of nailability.

The nails 18, with which the metal joist 10 is adapted to be secured to a collateral member, may be any suitable or conventional nails. A suitable nail is a No. 7 Helyx which is a hardened spiral-type nail.

Considering a specific dimensional example of the metal joist 10, shown approximately to scale in FIGURES 1 and 2, the chord members 12 and 14 may be constructed with both legs 23 and 24 having an overall width of 11/2 inches and a thickness in the major or principal portion thereof of 1A; inch. The minor intermediate portions 26 preferably have a steel thickness of 1A@ inch which provides good nail penetrability yet sufficient overall structural unity and rigidity for the chord member. The inside edge of the intermediate portion 26 may be located approximately 3A inch from the corner of the chord member and is approximately 1%; inch in width, thus leaving approximately 3/8 inch of the leg 24 extending from the outside edge of the intermediate portion 26. The vertical leg 23 is preferably substantially identical, for the above described manufacturing reasons. A metal joist 10 with chord members of these dimensions may be constructed lfor use for example in garden-type apartments with spans of up to 20 feet with the joists on two feet centers and with a 3A inch plywood subfloor to support a 60 pound per square vfoot iloor load. A Chord member of these dimensions provides a load capacity equal to or better than the conventional standard L-shaped angle having a 1% inch by 1% inch by 1/s inch section.

FIGURE 3 discloses a second embodiment of the invention in a metal joist 40, and FIGURE 4 discloses a further embodiment in a metal joist 50. The description hereinabove provided for the metal joist 10 is equally applicable to the metal joists 4G and Si) with the exception of the differences described hereinbelow. The principal differences are that the joists 40 and 50 each have top chords 42 and 52 respectively which are single unitary chords having a hat-shaped cross-sectional configuration and providing the function of both the chord members 12 and 14. The top chords 42 and 52 are adapted to be Welded along the top of their respective webs 44 and 54. The chords 42 and 52 may be formed by hot or cold rolling sheet steel of a uniform thickness into the desired hat configuration, simultaneously rolling the respective intermediate portions therein. The intermediate portions preferably correspond in configuration and position to the intermediate portion 26 described hereinabove for the metal joist 10. The joists 40 and 50 provide a nailable metal joist having the same advantageous characteristics as the metal joist 10.

It will be apparent from the foregoing description that the invention provides a nailable metal joist having numerous advantages over previous metal or wood joists. While the arrangement of the invention is at present considered to be preferred, it will be understood that variations and modifications may be made therein, and it is intended to cover in the appended claims all such variations and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A nailable joist for supporting a collateral member, said joist comprising:

web means;

elongated unitary structural steel load bearing chord `means joined to said web means,

said chord means having at least one imperforate flange portion which extends normally from said web means, said flange portion having a generally planar exterior surface adapted to abut the collateral member and an interior surface opposite said exterior surface,

the principal portion of said ange portion comprising nail impenetrable heavy guage steel,

and said flange portion having a minor intermediate portion deined by a single continuous groove extending into said interior surface of said flange,

said intermediate portion being thinner than said principal portion and nail penetrable.

2. The nailable joist of claim 1 wherein said chord means has a hat-shaped cross-sectional configuration.

3. The nailable joist of claim 1 wherein said chord means is a standard structural steel angle member with said groove rolled therein.

4. The nailable joist of claim 1 wherein said chord means comprises two standard steel angle L members, each said L member having two legs, with one said groove rolled in each said leg.

References Cited UNITED STATES PATENTS 1,221,941 4/1917 Witty et al. 52-364 1,918,346 7/1933 McHose 52-694 2,457,250 12/1948 Macomber 52-694 3,066,772 12/1962 Gibson 52-364 3,129,792 4/1964 Gwynne 52-364 3,164,227 1/1965 Davis et al. 52-364 FOREIGN PATENTS 695,591 8/1953 Great Britain.

FRANCIS K. ZUGEL, Primary Examiner. 

